The three-hour musical drew 18.6 million total viewers Thursday night as Underwood sang the part of Maria and "True Blood's" Stephen Moyer performed as Captain Von Trapp, the Los Angeles Times reported Saturday.

The large audience draw could foreshadow a shift in programming for networks, which are competing for viewers against Netflix, Amazon and even mobile phone apps like Instagram, the newspaper said.

"There is an edge to doing something live on TV [rather] than something pre-recorded, and it showed," said Brad Adgate, an analyst at ad firm Horizon Media in New York. "Anyone familiar with the movie saw different scenes from the Broadway show."

This type of live programming could be especially attractive for advertisers, which are seeing viewers fast forward through commercials as they watch shows on DVRs, the Times said.

"I thought it would have done 10 to 12 million ... not the 18-plus million," Adgate said. "We will definitely see more of this based on the ratings."

United Press International is a leading provider of news, photos and information to millions of readers around the globe via UPI.com and its licensing services.

With a history of reliable reporting dating back to 1907, today's UPI is a credible source for the most important stories of the day, continually updated - a one-stop site for U.S. and world news, as well as entertainment, trends, science, health and stunning photography. UPI also provides insightful reports on key topics of geopolitical importance, including energy and security.

A Spanish version of the site reaches millions of readers in Latin America and beyond.

UPI was founded in 1907 by E.W. Scripps as the United Press (UP). It became known as UPI after a merger with the International News Service in 1958, which was founded in 1909 by William Randolph Hearst. Today, UPI is owned by News World Communications.